In Uncharted 2: Among Thieves for the PS3, there are a lot of Boosters you can unlock for use in Multiplayer by reaching certain levels.
Here is the full list of Boosters you can unlock, what level is required to unlock them, and how much they cost after they are unlocked.
Booster Slot 1
Break Up – Level 10 – costs $11,250
Down the Irons – Level 14 – costs $18,750
Evasion – Level 50 – costs $210,000
From the Hip – Level 6 – costs $5,000
Glass Jaw – Level 57 – costs $1,500,000
Hell Blazer – Level 18 – costs $27,750
Invalid – Level 52 – costs $350,000
Juggler – Level 38 – costs $94,500
Point and Shoot – Level 2 – costs $2,000
Rapid Hands – Level 42 – costs $111,000
Situational Awareness – Level 46 – costs $129,000
Sure Shot – Level 30 – costs $64,500
Turtle – Level 22 – costs $40,500
Veiled – Level 51 – costs $300,000
Walk Softly – Level 34 – costs $79,500
Booster Slot 2
Bandoleer – Level 4 – costs $2,000
Come Get Some – Level 58 – costs $2,000,000
Deposit – Level 40 – costs $98,250
Explosive Expert – Level 20 – costs $32,250
Fleet Foot – Level 16 – costs $23,250
Half Loaded – Level 54 – costs $400,000
Keep Firing – Level 12 – costs $14,250
Launch Man – Level 28 – costs $58,500
Monkey Man – Level 32 – costs $72,000
Revenge – Level 48 – costs $134,250
Rocket Man – Level 44 – costs $120,000
Scavenger – Level 8 – costs $8,250
Scoped In – Level 36 – costs $87,000
Sure Foot – Level 26 – costs $52,500
Treasure Bearer – Level 24 – costs $43,500